Fabrication of glass microspheres with conducting surfaces

Abstract

A method for making hollow glass microspheres with conducting surfaces by adding a conducting vapor to a region of the glass fabrication furnace. As droplets or particles of glass forming material pass through multiple zones of different temperature in a glass fabrication furnace, and are transformed into hollow glass microspheres, the microspheres pass through a region of conducting vapor, forming a conducting coating on the surface of the microspheres.

I claim: 
     
       1. A method for fabricating hollow glass microspheres with conducting surfaces comprising; dropping liquid droplets or dried gel frits of glass forming material through a glass forming vertical oven having multiple regions of preselected temperature and length to form hollow glass microspheres; and   introducing a mist of conducting vapor into at least one region of the oven where the glass forming material has fused into glass to produce an atmosphere of conducting vapor through which the microspheres pass during the fabrication process to produce a conducting coating on the microspheres as part of the microsphere fabrication process.   
     
     
       2. The method of claim 1 wherein the vertical oven includes a high temperature fusing region where the glass forming material is transformed into glass microspheres. 
     
     
       3. The method of claim 2 wherein the fusing region includes a transition region where the glass forming material is transformed into glass microspheres and a refining region where the glass microspheres are further refined. 
     
     
       4. The method of claim 2 wherein the conducting vapor is introduced into the fusing region. 
     
     
       5. The method of claim 3 wherein the conducting vapor is introduced into at least one of the transition region and the refining region. 
     
     
       6. The method of claim 1 wherein the conducting vapor is a solution of a chloride of a metal selected from Tin, Platinum, Copper and Gold. 
     
     
       7. The method of claim 6 wherein the chloride solution is introduced in the oven by means of a carrier gas. 
     
     
       8. The method of claim 7 wherein the carrier gas is selected from Argon, Nitrogen and Carbon Dioxide. 
     
     
       9. The method of claim 7 wherein the carrier gas with conducting vapor is introduced into the oven at 5-15 psi. 
     
     
       10. The method of claim 6 wherein the conducting vapor is formed by vaporizing a solution of 60 g SnCl 4  -5H 2  0, 0.3 g, Ammonium Sulfate, 50 ml Methyl Alcohol, 25 ml Acetic Acid, and 15.5 ml water. 
     
     
       11. The method of claim 6 wherein the conducting vapor is formed by vaporizing a solution of 5 g anhydrous SnCl 4  in 1 ml water. 
     
     
       12. The method of claim 6 wherein the chloride solution is introduced into the oven by atomizing the solution. 
     
     
       13. The method of claim 1 wherein the conducting vapor is introduced in a region of the oven which is maintained at a temperature of at least about 375° C. 
     
     
       14. The method of claim 1 wherein the conducting vapor is introduced in a region of the oven which is maintained at a temperature of about 650° C. or higher.